Fluid flow regulation of a vehicle shock absorber/damper

ABSTRACT

Shock absorber components, such as a radial bypass damper, an anti-cavitation valve (ACV) and an incremental flow metering valve IFMV. The damper is of a continuous, unitary construction with a main hole and auxiliary holes interconnected by passageways. The ACV has openings that angle obliquely relative to entry surfaces of valving shims and extend at an incline continuously through the valving shims. The metering valve linearly regulates flow, substantially independent of piston displacement.

BACKGROUND OF THE INVENTION

The present invention relates to position sensitive radial bypass damper(RBD) components that regulate gas/oil flow of an off road vehicle shockabsorber. Such components may include a radial bypass damper housing, ananti-cavitation valve (ACV), and an incremental flow metering valve(IFMV).

Vehicle suspension undergoes dynamic movements as it negotiatesobstacles generally found in off-road racing venues. Shocks are providedto control wheel movement by resistance in off-road vehicles with suchsuspension. Such resistance arises from pressure forming on thecompression side of the working piston during the compression stroke andon the rebound side of the piston during the rebound stroke. Thenitrogen chamber, separated from the hydraulic oil by a floatingdividing piston, provides an opposing force on the said oil during thedynamic functions of the damper. Oil displacement and directional forcescompress and expand the nitrogen chamber but can induce cavitation ofthe oil within the damper itself if the transient response of thedividing piston from positive force to negative force is delayed(hysteresis).

The radial bypass damper of a vehicle shock absorber uses hydraulic oiltransfer to deflect valving shims that are located on both sides of theworking piston. Foaming of the hydraulic oil, or cavitation, is inherentto the dynamics inside the radial bypass damper, but may be avoided witha nitrogen gas chamber of the reservoir. The life of the radial bypassdamper is dependent on the longevity of the seals, wear bands, and thehydraulic oil itself. Preventing the damper from overheating is criticalto avoid the break down of the hydraulic fluid and seals from excessiveheat buildup caused by energy dissipation of the damper. However,conventional steel housings that typically have smooth tubing do notoptimize their surface area for cooling and therefore the air flow pastthe damper is not utilized as well for dissipating the extreme heatgenerated from damping an off road vehicle's suspension movements.

It would be desirable to provide components for an off road vehicleshock absorber that are suited to promote improved thermal management,weight savings, adjustability, durability, and adaptability to changingconditions.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention is to provide a radial bypass damper usefulin providing a shock absorption function that achieves a substantialreduction (1) in heat build up due to the use of a finned aluminum alloyhousing, (2) in weight by as much as 25% over a conventional steelhousing because of the aluminum alloy construction, and (3) in adversewear characteristics on piston wear bands from distortions in thehousing that arise due to welding external bypass tubes onto thehousing. Such welding is avoided with the invention.

Such a radial bypass damper comprises an elongated housing with a mainhole; at least one auxiliary hole spaced from the main hole, the mainhole and the at least one auxiliary hole being elongated in a directionof elongation of the housing and being free from intersecting eachother, the housing having an intervening housing material that iscontinuous and unbroken and arranged to space the main hole from the atleast one auxiliary hole, the housing having an intersecting passagewayextending between the main hole and the at least one auxiliary hole andnot beyond the at least one auxiliary hole.

Another aspect of the invention resides in valving shims in the workingpiston and in an ACV that have continuous, inclined passages forhydraulic oil flow to prevent cavitation during sudden changes ofdirectional travel of the working piston and to maintain positivepressure at the working piston. The ACV with such valving shims permitslower nitrogen gas pressure to prevent cavitation of the oil over thatof conventional shock absorbers not equipped with a like ACV, yetreduces pressure generated at its piston rod. This effectively improvesthe performance of the shock absorber and increases positive feed backto the driver by reducing the harshness incurred by sharp increases inforce when the shock absorber compresses over rough surfaces.

A further aspect resides in an IFMV that permits adjustments to thebypass of fluid at different points of up and down travel. Accurateadjustment is available without the need to visually see the indexpoints, because of a detent ball assembly providing an audible “click”and feel at each setting.

Such an IFMV, comprises a valve housing having a passage for fluid flowthrough the valve housing, a piston configured to move in response toapplication of fluid forces toward and away from a position that closesthe passage; and a flow regulating mechanism including a regulatorarranged to regulate flow of fluid through the passage, the flowregulating mechanism including a plurality of selectable settings thatare accessible from outside the valve housing and including a regulatormovable to vary a dimension of at least a portion of the passage inaccordance with a selected one of the selectable settings so as toprovide a substantially linear variation in the flow of fluid throughthe passage as the regulator moves to a position corresponding to theselected one of the selectable settings, the flow regulating mechanismproviding regulation of the flow of fluid through the passagesubstantially independent of movement of the piston as long as thepiston is away from a position that closes the passage.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is madeto the following description and accompanying drawings, while the scopeof the invention is set forth in the appended claims.

FIG. 1 is an isometric view of the shock absorber in accordance with theinvention.

FIG. 2 is an isometric view of the radial damper housing of the shockabsorber of FIG. 1.

FIG. 3 is a schematic representation of the compression stroke of theworking piston within the radial bypass damper, showing the relativeflow within the correlating bypass.

FIG. 4 is a schematic representation of the compression stroke of theworking piston within the radial bypass damper, showing the point atwhich the bypass function is no longer actuated.

FIG. 5 is an end view of the radial damper housing of FIG. 3.

FIG. 6 is a transverse cross section midway along the radial damperhousing of FIG. 3.

FIGS. 7-10 are longitudinal cross sections of the radial damper housingof FIG. 2 across the main hole and respective ones of the auxiliaryholes.

FIG. 11 is an end view as in FIG. 5, but marked with notation forindicating the manufacturing procedure.

FIG. 12 is a longitudinal view taken across 12-12 of FIG. 11 and markedwith notation for indicating the manufacturing procedure.

FIG. 13 is a schematic representation of a drilling procedure to form aninterconnecting passageway in between main and auxiliary holes of theradial damper of FIG. 2.

FIG. 14 is an isometric view of a drilling tool used in the drillingprocedure of FIG. 13.

FIG. 15 is a schematic representation of the shock absorber of FIG. 1showing the flow direction during the compression (bump) stroke of theworking piston, between the working piston, the hose and the ACV.

FIG. 16 is a schematic representation of the shock absorber of FIG. 1showing the flow directions during the extension (rebound) stroke of theworking piston, between the working piston, the hose and the ACV.

FIG. 17 is an isometric view of the ACV assembly installed in thereservoir end cap.

FIG. 18 is an isometric cutaway view midway across the ACV of FIG. 17.

FIG. 19 is an isometric view of the rebound face of the ACV and washerof the valving shims of FIG. 17.

FIG. 20 is an exploded view of the components of the working pistonincluding valving shims.

FIG. 21 is a schematic representation of flow direction through the IFMVin place in an auxiliary hole of the radial damper housing.

FIG. 22 is a cross-section of a portion of an auxiliary hole of theradial damper housing into which is to be fitted the IFMV.

FIG. 23 is a side view of the IFMV that is represented schematically inFIG. 21.

FIG. 24 is an isometric view of the IFMV of FIG. 23.

FIG. 25 is a side view of the IFMV of FIG. 23 but with portions showntransparent that otherwise block portions underneath from view.

FIG. 26 is an exploded view of the components of the IFMV of FIG. 25.

FIG. 27 is a graph of the force/velocity change at each of the settingsof the IFMV of FIG. 23.

DETAILED DESCRIPTION OF THE INVENTION

Off-road racing vehicles include those in a truck-race, buggy-race,lifted truck recreational, sand car-recreational, monster truck andmilitary specialty vehicles. The function of the shock absorber 20(FIG. 1) of the invention is to permit such off road racing vehicles topass over extremely rough terrain at high speeds with improved controland stability.

The shock absorber 20 includes a radial bypass damper housing 22 havinga chamber in which moves a working piston and shaft 24 to effectcompression and rebound strokes. A hose 26 connects the opposite end ofthe chamber with an oil gas reservoir 28.

Turning to FIG. 2, the radial bypass damper housing 22 is made ofaluminum alloy and formed without welds. The housing of the radialbypass damper housing 22 may be formed from extruded 6061-T6 aluminumalloy that is manufactured in solid profile in fixed lengths. Theprofile of the radial bypass damper housing 22 incorporates coolingfins, which in turn offer substantially more surface area and materialto disperse the heat during operation and direct airflow than smooth,un-finned surfaces.

When the invention was tested in operation, temperature indicatorsshowed that the operating temperatures that are experienced are lowerthan when steel dampers are used. Also, higher vehicle speeds wereattained than for other damper types installed on test vehicles on thesame course. Inspection of components that are susceptible to wearshowed improvement in reduced wear and reduced failure in long-termservice over conventional dampers tested. Such performance gains signifythe realization of serviceability and cost savings in operation duringthe life of the damper.

The fixed lengths are cut to suit installation for an off-road vehicle.The different lengths for longitudinal auxiliary holes (bypasspassageways) 30 are cut to the appropriate dimensions. The longitudinalauxiliary holes 30 are machined into the solid parts by a gun-drillingprocedure. The main hole (cylinder) 32 is precision bored.

FIGS. 3 and 4 show respectively the compression strokes of the workingpiston 24 within the main hole 32 of the radial bypass damper housing22. As best seen in FIGS. 5-10, there are two longitudinal auxiliaryholes (bypass passageways) 30 that allow the oil to bypass through thetwo longitudinal auxiliary holes depending upon the position of theworking piston during the compression stroke with respect to theintersecting ports 34. There is no bypass function performed by thesetwo longitudinal auxiliary holes (bypass passageways) 30 during therebound stroke. However, there are two other longitudinal auxiliaryholes (bypass passageways) that provide bypass function during therebound stroke depending upon the position of the working piston 24during the rebound stroke with respect to the intersecting ports 34. Thelongitudinal auxiliary holes 30 widen into a chamber 36 at an end andinto which is to be inserted an IFMV.

As the working piston 24 travels towards the open intersecting ports 34,the oil flows in the opposite direction, deflecting the piston of theIFMV 38. The oil then flows through the IFMV 38 at a preset position andto the backside of the working piston 24. This is the bypass function ofthe radial bypass damper housing 22 during the compression stroke. Thelocation of the open intersecting ports varies and is reliant on thetotal stroke length of the working piston 24 within the radial bypassdamper housing 22.

When the working piston 24 covers the open-intersecting bypass port 34,the bypass function becomes disengaged entirely. This is also true asthe working piston 24 travels beyond the bypass port 34. This samedynamic function is observed during the rebound stroke of the workingpiston 24 with the incremental metering flow valve 38 located at theopposite end of the bypass port, thereby governing the flow in theopposite direction from what is viewed in FIG. 4.

During the rebound stroke, the incremental metering flow valve 38 seesequal pressure on both sides of its piston and will remain closed, orinactive. When the working piston 24 is beyond the bypass ports in itscompression stroke, the valving found in the working piston 24 and theACV 40 is governing flow/resistance in its entirety, thus no additionalbypass is in use.

The radial bypass damper housing 22 of the invention preferably has nowelds and the longitudinal auxiliary holes 30 and main hole 32 aremanufactured precisely straight and true to provide longer wear bandservice life, less frictional resistance and reduced heat build up ascompared to having external bypass tubes welded onto the housing. Suchwelding gives rise to unwanted distortions that create adverse wearcharacteristics on piston wear bands. After machining, the housing ofthe damper is preferably hard anodized to specification MIL-A-8625FClass 1, type III for corrosion and wear resistance.

The radial bypass damper housing 22 acts as a heat sink. It dissipatesthe heat built up from damping energy by transferring it outward throughthe surface area of the profile provided by the cooling fins 42 andexternal profile. Analogous to a radiator, airflow over the damperhousing improves the cooling performance and stabilizes the temperatureat a lower level for the duration of a race with the off-road vehicle.The rate of cooling has been tested and found to reduce peaktemperatures by as much as 100 degrees F., which constitutes as much asa 33% reduction in temperature. Steel shock tubes under the same testconditions often reach peak temperatures of 325 degrees F. and above.

FIGS. 11 and 12 illustrate the steps in the manufacturing procedure forthe radial bypass damper housing 22. An aluminum alloy extrusion processis used, the steps of which are conventional for extruding aluminumalloy housings, albeit unique as it applied to the damper housing of theinvention. A tool-die is made with the parts cross-sectional profilemachined in its center. The outer features of the damper housing areincorporated in to the tool-die. The die is placed in a conventionalextrusion apparatus and semi-molten aluminum alloy is forced through thedie at high pressure and cooled upon exit to maintain the shape withminimal distortion over a 12′ length. The steps of manufacture are: 1.Initially solid profile of aluminum alloy is extruded, such as in 12foot lengths. 2. The solid profile is cut to desired lengths, e.g., fourdifferent lengths. 3. The main hole (cylinder) is located, e.g., 3 inchdiameter. 4. Radial bypass bosses are milled to length. 5. Thelongitudinal auxiliary hole centers are located. 6. The longitudinalauxiliary holes are gun drilled. 7. The main hole is precision bored andhoned to specification. 8. Bypass counter bores and threading is made.9. Main hole counter bores and threading is made. 10. Intersectingbypass ports are drilled. 11. Surface finish and cleanup are performed.12. Hard anodized clear, MIL-A-86256, Class 1-Type III is conducted. 13.Logo is milled onto housing.

A drilling process (FIG. 13) is performed from the inside of the radialbypass damper housing 22 outward through intervening walls 44 (FIGS.7-10). An appropriate drilling tool 52 (FIG. 14) is used to perform adrilling process for forming intersecting passageways 34 between themain hole 32 and respective ones of the longitudinal auxiliary holes 30.This drilling process is not from the outside inward through theexterior of the longitudinal auxiliary holes and thus eliminates theneed for external plugs and potential seal failures that otherwise arepresent conventionally with steel tubes where the exterior of thelongitudinal auxiliary holes are drilled into from the outside. Counterbores are made at the ends of the auxiliary holes and main hole toaccommodate the insertion of further components, such as IFMVs.

Turning to FIGS. 15 and 16, compression and rebound strokes of theworking piston 24 and their effect on flow through valving shims of theACV 40 (FIG. 17) are depicted. Deflective disks (or valving shims)(FIGS. 17, 18) that form a valve stack are used to tune the amount offlow/resistance in both compression and rebound strokes of a mono-tubedamper. The shims are found primarily on the active/working piston 24within the damper housing 22 (FIG. 24), but may also be used inconjunction with a base valve/ACV (FIGS. 15, 17). The greatest diametershim found directly on the surface of the piston/base valve is called acover disc and jointly acts as a check valve, governing oil flow in theopposite direction during the rebound or compression stroke of thedamper.

Referring to FIGS. 17 and 18, the ACV 40 is a tuning tool that permitsfar less gas pressure to achieve the task of preventing oil cavitation(foaming). An ACV 40 is more commonly associated with twin-tube shockdesign because it is fixed toward the base of the internal shock tubeand generally is without a gas chamber. In mono-tube shock design, thelocation is much the same but with the option of moving it into a remotereservoir with the gas chamber and dividing piston.

The ACV 40 is stationary and located in the reservoir end cap betweenthe floating piston, which separates a nitrogen gas chamber from theoil, and the working piston. Its function is not affected by either ofthe aforementioned locations. The base valve 40 enhances the effects ofa damper's nitrogen chamber. The nitrogen gas chamber provides areactive force on the hydraulic oil, and prevents cavitation of the oil.This is an inherent byproduct of flowing fluid past solid objects athigh velocity, i.e. the working piston and valve shims. Cavitation isthe sudden formation and collapse of low-pressure bubbles in liquids bymeans of mechanical forces, such as those resulting from propellerrotation.

The dividing piston will move relative to oil displacement caused by thepiston rod plunging in or out of the damper, while maintaining force onthe oil due to the nitrogen chambers ability to compress and expand. Theside effect is that the gas pressure rises significantly as the chamberis reduced in size. This creates force on the piston rod effectivelyadding “spring rate”. In other words, the gas force wants to push thepiston rod back out of the damper. This force is like a spring on avehicle and can increase the resistance put upon the vehicles “sprungweight” and change the dynamics of the vehicles handling and feel. Asudden ramp-up of gas force when the piston rod displaces the oil canmake a vehicle feel very harsh over rough terrain, effectively losingtraction and “detaching” the driver from feedback through vehicle.

The ACV 40 is tuned to maintain pressure between the working piston andreservoir when the shock is in transition from compression to reboundstrokes. It works with the nitrogen chamber to reduce the chance ofcavitation during sudden changes of directional travel of the piston butwith upwards of 175% less psi. Without the ACV 40, the gas pressure mustbe set to 200-250 psi static to help the piston respond quickly to therebound stroke. However, the inherent lag in transient response, orhysteresis, can cause an air pocket to form at the head of the workingpiston. Hysteresis is the lagging of a physical effect on a body behindits cause (as behind changed forces and conditions).

When the working piston 24 goes into its rebound stroke, the dividingpiston must respond by changing direction as well. In other words, thegas pressure expands when the force changes from compression toextension. This is the dynamic point of action that can inducecavitation at the working piston. Without a quick response, an airpocket can form in the main damper cylinder, directly affecting theperformance of the damper throughout the duration of a race or hard use.This air pocket is found in between the hose inlet and the workingpiston. With each stroke, the air pocket would continue to disperse toboth sides of the working piston and bypass ports, causing what iscalled “fade”. The working piston 24 will lose its ability to generatethe needed resistance to the dynamic motions of the vehicle and itssuspension, allowing the tires to lose contact or allow the vehicle tobottom out it's suspension travel.

The ACV 40 is fixed in place by an internal retaining ring and permitseasy servicing and tuning. The remote reservoir housing contains the gaschamber, which is separated from the hydraulic oil with a floatingdividing piston. The ACV 40 reduces the required gas pressure by as muchas 130-175% as compared to conventional products. As in the workingpiston 24 of the shock absorber, the ACV 40 uses valving shims to governthe flow of oil and maintain positive pressure at the working piston.Charge pressures are reduced from as much as 250 psi to a minimum of 50psi, effectively reducing the gas spring force on the piston rod andtherefore reducing measurable spring rate. The rod force of a shockabsorber not equipped with the ACV 40, charged to 200 psi, was measuredat 338.32 lbf (1504.83 N) when compressed. The rod force of the sameshock absorber equipped with the ACV 40 and charged to 60 psi wasmeasured at 101.49 lbf (451.45 N). No performance lag (indicatingcavitation) was observed when tested on a dynamometer.

Turning to FIG. 19, the cover plate valving shim 58 has threecompression ports 54 that are angled into a tuned valve stack, which islocated on opposite side, as viewed. The cover plate valving shim 58 hassix rebound ports 56 that allow the reverse flow through the ACV 40 tooccur, only having to actuate a single lightly rated deflective shim.This shim 58 acts as a directional valve with minimal resistance to theflow of oil on rebound. The heavy washer 60 is shimmed a particulardistance away from the cover shim and acts as a stop plate. A fastener62 through the center of the valving shims keeps the valving shimassembly together. Only the required amount of deflection to allowmaximum flow is needed and limiting the cover shim at that point reducescycle fatigue.

Opposite from that of the working piston, the greater number of ports inthe ACV 40 are utilized for the rebound stroke, and the lesser forcompression. The ACV 40 must permit the dividing piston to react asquickly as possible during its rebound travel and therefore reboundforce must be relieved effectively. In contrast, the compression portsof the ACV 40 are fewer and are restricted with a tuned valving stack,much like the working piston within the radial bypass damper. The intentbeing to prolong a built up force under compression stroke between theworking piston and the ACV 40.

Conventionally bypass dampers that are position sensitive includevariable flow metering check valve assemblies. The off-road industry hasused several variations of bullet style check valve pistons withcontoured valve seat that are adjusted by a threaded stop-pin thatlimits the distance the piston can travel. The amount of flow isgoverned at this piston and its mating/sealing surface.

FIG. 20 shows some exemplary components of the working piston 24, suchas a nut 64, washer 66, valving shims 68, wear band 70, O-ring 72,piston 74, washer 76, piston rod 78, bearing spacer 80, bearing cup seal82, internal retaining ring 84, spherical bearing 86 and rod end 88. Thevalving shims 68 may include the cover plate valving shim 58 of FIGS.18-19, except arranged in a reverse orientation in that more flow isneeded during the compression stroke for regulation but flow may berestricted during the rebound stroke.

Turning to FIGS. 21, 23-26, the present invention encompasses an IFMV 38for whose piston travel is not limited until maximum flow through thevalve occurs. That is, its piston does not limit the regulation of flowat all. Instead, a flow regulating mechanism 90 is provided thatincludes a triangular port assembly located at one end of the bypassport to govern the flow bypass adjustments. The IFMV 38 is positionedwithin the cavity 36 (FIG. 22) at an end of each of the longitudinalauxiliary holes 30.

The triangular port assembly includes an opening 92 that is shaped likean isosceles triangle to allow for precise monitoring of the bypass. Twoopposed triangular ports are machined into the valve housing, positiondiametrically across from each other. The flow regulating mechanismincludes a flow regulator 94 that is rectangular in shape to sweep pastthe triangular shaped ports to create a linear change in the rate offlow, i.e. increase or decrease as applicable depending upon theunobstructed dimension through the triangular ports.

The actuation of the IFMV 38 is adjusted externally and hassure-indexing features 96. The valve is a one-piece unit sealed withBuna O-rings that prevent oil from escaping and prevent dirt and waterfrom entering. A spring-loaded detent ball 98 is arranged to provide andaudible click and feel as it is moved along each of the selectablesettings. The valve cannot be rotated beyond a ninety-two degree rangedue to internal features and each selectable setting is marked on thevalve housing.

The valve has a hex head 100 that may be readily accessed with a wrenchor socket to turn as desired. The regulator 92 moves in unison with theturning of the hex head 100. Likewise, either the spring-loaded detentball 98 or the selectable settings 96 move in unison with the turning ofthe hex head 100 as well. Thus, turning of the hex head 100 isaccomplished with a single tool, even when the valve is not easilyvisible. Preferably, the valves are color coded for both bump(compression) and rebound (extension).

The check valve piston 102 has a contoured face that seats against amachined tapered surface and provides smooth, uninhibited flow of thehydraulic oil. All of the edges of the piston are rounded, therebyreducing cavitation as the oil flows past them. A linear coil spring 104assists in returning the piston to its position against the sealingsurface when flow changes direction. The pressure generated by theworking piston governs how far the IFMV must travel to permit the flowof oil to bypass it without restriction. Bleed ports 106 are provided inthe piston head to allow oil to flow out of the cavity between theinternal bore of the IFMV piston 108 and the guide pin 110, preventinghydraulic lock. This in turn allows the piston to reciprocate quicklyand without delay.

Also shown in FIG. 25 are O-rings 112, the valve housing 114, and thesocket head cap screw used to secure the IFMV into a pair of receivingscrew holes 116 at the end of the longitudinal auxiliary holes 30 (FIG.5)

Each radial bypass damper has four IFMV assemblies, two for bump(compression) and two for rebound (extension). The position of theassembly is dependent on the travel length of the radial bypass damper.

Each setting of the IFMV 38 changes the force/velocity, eitherpositively or negatively, in a linear fashion. FIG. 27 shows a graph ofthe force/velocity change, which is indicative of the separationachieved with each setting on the rebound/bump stroke of the shockabsorber.

While the foregoing description and drawings represent the preferredembodiments of the present invention, it will be understood that variouschanges and modifications may be made without departing from the scopeof the present invention.

1. An apparatus useful to regulate fluid flow, comprising an elongatedhousing with a main hole; at least one auxiliary hole spaced from themain hole, the main hole and the at least one auxiliary hole beingelongated in a direction of elongation of the housing and being freefrom intersecting each other, the housing having an intervening housingmaterial that is continuous and unbroken and arranged to space the mainhole from the at least one auxiliary hole, the housing having anintersecting passageway extending between the main hole and the at leastone auxiliary hole and not beyond the at least one auxiliary hole.
 2. Anapparatus of claim 1, wherein the intervening housing material is freeof welds between the main hole and the at least one auxiliary hole. 3.An apparatus of claim 1, wherein the housing is formed free of any plugsbetween any of the auxiliary holes and outside of the auxiliary holesthat are in alignment the intersecting passageway.
 4. An apparatus ofclaim 1, wherein the housing is formed of aluminum alloy.
 5. Anapparatus of claim 1, wherein the intervening housing material is of asubstantially, uniform composition throughout an entirety of thehousing.
 6. An apparatus of claim 1, wherein the housing includes finsprojecting outward from an exterior of the housing, the fins beingformed of material that is substantially identical to the interveninghousing material.
 7. An apparatus of claim 6, wherein the fins areconfigured so that a rate of cooling from external flows of a coolingmedia reduces peak temperatures during back and forth motion of a pistonof a shock absorber within the main hole by as much as 100 degreesFahrenheit as compared to steel stock tubes under same conditions due tothe back and forth motion that reach peak temperatures of at least 325degrees Fahrenheit.
 8. An apparatus of claim 1, wherein the housing hasmachined and anodized surfaces to effect resistance to corrosion andwear.
 9. An apparatus of claim 1, further comprising a shock absorberpiston arranged within the main hole movable back and forth to effectcompression and rebound strokes that cause oil to flow, the at least oneauxiliary hole including two pairs of the auxiliary holes, each of thepairs including auxiliary holes of different lengths, a first of the twopairs of the auxiliary holes being formed to during the compressionstrokes and conveying oil through a second of the two pairs of theauxiliary holes during the rebound strokes
 10. An apparatus of claim 1,wherein the housing is free of further holes that extend from a hollowof the at least one auxiliary hole to outside of the housing.
 11. Amethod of forming an apparatus useful to regulate fluid flow, comprisingthe steps of forming a main hole and at least one auxiliary hole in anelongated housing, the main hole and the auxiliary hole being elongatedin a direction of elongation of the housing; arranging the main hole andthe at least one auxiliary hole to avoid intersecting one another andspacing the main hole from the at least one auxiliary hole by anintervening housing material that is continuous and unbroken, andforming an intersecting passageway from the main hole through theintervening housing material to the at least one auxiliary hole but notbeyond the at least one auxiliary hole.
 12. A method of claim 11,further comprising forming the intervening housing material free ofwelds between the main hole and the at least one auxiliary hole.
 13. Amethod of claim 11, further comprising forming the housing free of anyplugs between any of the auxiliary holes and outside of the auxiliaryholes that are in alignment the intersecting passageway.
 14. A method ofclaim 11, further comprising forming the housing of aluminum alloy. 15.A method of claim 11, further comprising forming the intervening housingmaterial of a substantially, uniform composition throughout an entiretyof the housing.
 16. A method of claim 11, further comprising projectingfins outward from an exterior of the housing, the fins being formed ofmaterial that is substantially identical as the intervening housingmaterial.
 17. A method of claim 16, further comprising configuring thefins so that a rate of cooling from external flows of a cooling mediareduce peak temperatures during back and forth motion of a piston of ashock absorber within the main hole by as much as 100 degrees Fahrenheitas compared to steel stock tubes under same conditions due to the backand forth motion that reach peak temperatures of at least 325 degreesFahrenheit.
 18. A method of claim 11, further comprising machining andanodizing surfaces of the housing to effect resistance against corrosionand wear.
 19. A method of claim 11, further comprising arranging a shockabsorber piston within the main hole to move back and forth to effectcompression and rebound strokes that cause oil to flow, the at least oneauxiliary hole including two pairs of the auxiliary holes, each of thepairs including auxiliary holes of different lengths, conveying oilthrough a first of the two pairs of the auxiliary holes during thecompression strokes and conveying oil through a second of the two pairsof the auxiliary holes during the rebound strokes.
 20. A method of claim11, further comprising forming the housing free of further holes thatextend from a hollow of the at least one auxiliary hole to outside ofthe housing and that are in alignment with the interconnectingpassageway.